Image contrast refers to measurement of different luminance levels between the brightest color “white” and the darkest color “black” in an image. The larger the difference between the brightest color “white” and the darkest color “black” is, the larger the image contrast is. The smaller the difference between the brightest color “white” and the darkest color “black” is, the smaller the image contrast is. The adjustment of image contrast adjustment may improve the display effect of an image. A conventional method for adjusting the image contrast is implemented as follows. An image is converted into a HSV (Hue, Saturation, Value) color space or a LAB (L represents luminance, A represents a range from carmine to green, and B represents a range from yellow to blue) color space. And then, a luminance curve of luminance component (V or L) is adjusted to change a luminance relationship between a pixel before adjustment and the pixel after adjustment, thereby adjusting the image contrast.
However, the adjusted image that is obtained by the conventional method for adjusting the image contrast cannot fully represent details of the image, and may destroy the distribution of bright and dark regions of the image. Accordingly, an ideal image adjustment effect cannot be obtained by the conventional method for adjusting the image contrast.